Only 7% of our DNA is unique to modern humans

Only 7% of our DNA is unique to modern humans
Only 7% of our DNA is unique to modern humans

What makes a person unique? Scientists have taken another step towards solving the eternal mystery with the help of a new tool that could allow more accurate comparisons of the DNA of modern people with the DNA of our extinct ancestors.

According to a study published Friday in the journal Science Advances, just 7% of our genome is unique and has no commonalities with other people, as well as with other early ancestors.

Nathan Schaefer, a computer biologist at the University of California and co-author of the new work, said:

"That's a pretty small percentage. This is why scientists abandon the idea that we humans are so different from Neanderthals."

The study used DNA extracted from the fossil remains of the now extinct Neanderthals and Denisovans, dating from about 40,000 or 50,000 years ago, as well as from 279 modern humans around the world.

Scientists already know that modern humans share DNA with Neanderthals, but different people have different parts of the genome. One of the goals of the new study was to identify genes that are unique to modern humans.

This is a complex statistical task, and the researchers "have developed a valuable tool that accounts for missing data in ancient genomes," said John Hawkes, a paleoanthropologist at the University of Wisconsin at Madison.

The researchers also found that an even smaller portion of our genome - just 1.5% - is both unique to our species and common to all living humans. These stretches of DNA may contain the most important clues about what really sets modern humans apart.

"We can say that these regions of the genome are highly enriched in genes associated with neural development and brain function," says co-author of the article, computational biologist Richard Green of the University of California, Santa Cruz.

In 2010, Greene helped draft the first draft of the Neanderthal genome sequence. Four years later, geneticist Joshua Eiki co-wrote a paper in which he showed that modern humans carry some remnants of Neanderthal DNA. Since then, scientists have continued to improve methods for extracting and analyzing genetic material from fossils.

"Better tools allow us to ask ever more detailed questions about human history and evolution," said Eiki, who now works at Princeton and was not involved in the new study. He praised the methodology of the new study.

The findings highlight that "we are actually a very young species," Eiki said. "Not too long ago, we shared the planet with other human species."

Popular by topic